马安大桥岩溶区成桩加固处理施工技术

Pile Formation and Consolidation at Karst Area of Ma′an Bridge

马安大桥桥址处于溶洞发育地区,基础为准1500mm、准1300mm钻孔灌注桩基础,桩基持力层灰岩裂隙极发育,分布着大大小小、半填充、全填充或无填充的溶洞。桩基按常规工艺进行施工时,在施工过程中陆续出现孔内泥浆骤降,孔壁坍塌及地表坍塌沉陷等现象,本文介绍岩溶区成桩及加固处理技术。

Ma′an Bridge is located at the area with karst caves and of ?准150cm & ?准130cm bored cast-in-situ concrete piled foundation. At the bearing course of the pile foundation, there developed a lot of fissures and distributed semi-filled, fully filled or non-filled karst caves of different sizes. During construction of pile foundation with conventional technology, the phenomena such as sudden drop of mud in hole, collapse of cave wall and collapse & settlement of ground surface, etc. happened during construction. This paper mainly introduces the pile formation and consolidation construction technology.